The Hanuman Langur (Semnopithecus entellus) is the most widely distributed nonhuman primate in South Asia. It is found throughout most of India and Sri Lanka and is also established in parts of Pakistan, Nepal, Bhutan, and Bangladesh. Hanuman Langurs occur in a wide range of habitats, from arid regions on the edge of the desert in Rajasthan to the rain forests of Western Ghats, and at altitudes from 100 m above sea level to 4270 meters above sea level in the Himalayas. Although Hanuman langurs are among the most well known, revered, and extensively studied nonhuman primates in India, the taxonomic status of this species has remained unresolved. Hanuman langurs exhibit a high degree of morphological variation throughout their range, which is reflected in the multitude of classification schemes proposed to resolve the taxonomic status of these monkeys. Thus, although most authors have considered the Hanuman langur to be a single species, others have split this species into 2, 3, 4, 7, or as many as 14, 15, or even 16 species. Resolving this taxonomic uncertainty will require more extensive geographic sampling and genetic and morphological analysis (Karanth et al., 2008; Osterholz et al., 2008; Karanth et al. 2010; Nag et al. 2011 and references therein).

The diet of the Hanuman Langur consists mainly of leaves, fruit, buds, and flowers, as well as some insects. Those living near humans sometimes raid gardens and crops. Troops living near temples may rely on human offerings. In the Himalayas, during snowy winter months they rely on pine cones, bark, and twigs. Hanuman Langurs are diurnal, terrestrial, and arboreal—in fact, they are the most terrestrial of any colobine monkey. Up to 80% of the day is spent on the ground and nearly all feeding takes place within 5 m of the ground. In single-male groups, tenure of the alpha male is usually less than 2 years. The new alpha male systematically kills infants sired by previous alpha male. Hanuman Langurs sleep in trees and high places—including hotel ledges! This is the sacred monkey of India, named after the Hindu monkey-god Hanuman. (Rowe 1996 and references therein)